This invention relates to a bagging specification adjustment and automatic inward-contraction and outward-expansion mechanism for a machine for packaging material in bags and particularly to a single mechanism that can adjust the distance between the claw arms subject to the specification of the mouth of the bag. During the operation, it also permits the claw arms to form an automatic inward contraction at a specific position and together with the external vacuum sucking pads allows the mouth of the bag to expand during the charging phase. Upon the completion of the charge, the claw arms expand outwardly to allow the mouth of the bag to collapse for thermal sealing treatment.
To match the specification of the mouth of the bag in the conventional disc-type bagging machine, typically the claw arms are constructed as shown in FIG. 1 according to ROC Pat. 147095 with an appropriate numbers of screw and screw hole thereon and claws removably mounted. Wishing to adjust the machine in accordance with the specification of the bags, one has to unlock each screw station to station. In FIG. 1, there are six stations having a total of 12 claw arms and 24 pieces of screws and it is necessary to dismount these 12 claws for relocation corresponding to the specification of the bags. In addition to the trouble of complicated dismounting, this construction is adjustable to fit a limited range of specifications.
In addition, for the charging operation, the conventional machines need to pull the claw arms with a pneumatic cylinder or similar equipment and together with the vacuum sucking pads on each side of the bag respectively for sucking each side of the mouth so as to force it to expand. At the end of the charging operation, some method is needed to force the mouth to collapse gradually for the subsequent thermal sealing treatment.